Ensure stable identity for pricing tiers in forms

Adds a tempId to new pricing tiers for stable mapping before backend _id assignment. Updates mapping logic in pricing-tiers form to use tempId or _id for reliable event handling and rendering.

components/forms/pricing-tiers.tsx

@@ -76,14 +76,12 @@ export const PricingTiers = ({
             .sort((a, b) => (a?.minQuantity || 0) - (b?.minQuantity || 0))
             .map((tier, sortedIndex) => {
               if (!tier) return null;
-              
-              // Find the original index for proper event handling
-              const originalIndex = pricing.findIndex(p => 
-                p === tier || (p?.minQuantity === tier?.minQuantity && p?.pricePerUnit === tier?.pricePerUnit)
-              );
+              // Prefer stable identifiers for mapping back to the original array
+              const keyId = tier._id || tier.tempId;
+              const originalIndex = pricing.findIndex((p) => (p?._id || p?.tempId) === keyId);
               return (
             <div
-              key={tier._id || originalIndex}
+              key={keyId || originalIndex}
               className="grid grid-cols-[1fr_1fr_1fr_auto] gap-2 mt-2"
             >
               <Input

components/modals/product-modal.tsx

@@ -98,7 +98,19 @@ export const ProductModal: React.FC<ProductModalProps> = ({
   const handleAddTier = () => {
     setProductData((prev) => ({
       ...prev,
-      pricing: [...prev.pricing, { minQuantity: 0, pricePerUnit: 0 }],
+      pricing: [
+        ...prev.pricing,
+        {
+          minQuantity: 0,
+          pricePerUnit: 0,
+          // tempId ensures stable identity before backend assigns _id
+          // Using crypto.randomUUID if available, otherwise a timestamp fallback
+          tempId:
+            (typeof crypto !== "undefined" && (crypto as any).randomUUID
+              ? (crypto as any).randomUUID()
+              : `${Date.now()}-${Math.random()}`),
+        },
+      ],
     }));
   };